played the entire game, got the boss at the end, now this is my opinion, but I dont like the sliding movement very much, remove it if you can, add health to the characters, I ended up only using the axe girl, make some puzzles that you need to change the hero, and the final boss, remove the timer of no damage, if you want it to be harder to kill, dont make it harder by time, make it because the boss atacks you with recularity that you need to stay away from him.
overall, nice game entry for a start.
cheers